Manufacture method of black matrix

ABSTRACT

The present invention provides a manufacture method of a black matrix. The COA technology is utilized to manufacture the organic photoresist blocks with a larger thickness on the alignment marks. Then, the black matrix thin film covers on the organic photoresist blocks to tremendously increase the level differences of the positions of the alignment marks and adjacent areas. Thus, the contour recognition apparatus is employed to accurately recognize positions of the alignment marks. The issue that the alignment marks are difficult to be recognized after the black matrix thin film is coated in the BOA process can be solved.

FIELD OF THE INVENTION

The present invention relates to a display technology field, and moreparticularly to a manufacture method of a black matrix.

BACKGROUND OF THE INVENTION

With the development of display technology, the flat panel device, suchas Liquid Crystal Display (LCD) possesses advantages of high imagequality, power saving, thin body and wide application scope. Thus, ithas been widely applied in various consumer electrical products, such asmobile phone, television, personal digital assistant, digital camera,notebook, laptop, and becomes the major display device.

Most of the liquid crystal displays on the present market are back lighttype liquid crystal displays, which comprise a liquid crystal displaypanel and a back light module. The working principle of the liquidcrystal display panel is to locate liquid crystal molecules between twoparallel glass substrates, and a plurality of vertical and horizontaltiny electrical wires are between the two glass substrates. The light ofback light module is reflected to generate images by applying drivingvoltages to control whether the liquid crystal molecules to be changeddirections.

Generally, the liquid crystal display panel comprises a CF (ColorFilter) substrate, a TFT (Thin Film Transistor) array substrate, LC(Liquid Crystal) sandwiched between the CF substrate and TFT substrateand sealant. The formation process generally comprises: a forepart Arrayprocess (thin film, photo, etching and stripping), a middle Cell process(Lamination of the TFT substrate and the CF substrate) and a post moduleassembly process (Attachment of the driving IC and the printed circuitboard).The forepart Array process is mainly to form the TFT substratefor controlling the movement of the liquid crystal molecules; the middleCell process is mainly to add liquid crystal between the TFT substrateand the CF substrate; the post module assembly process is mainly thedriving IC attachment and the integration of the printed circuit board.Thus, the liquid crystal molecules are driven to rotate and displaypictures.

In the traditional liquid crystal display panel, At one side of thecolor filter, a layer of BM (Black Matrix) is manufactured which isemployed to divide adjacent color resists to shield the gaps of thecolor resists and to prevent the light leakage or the color mix; theskill of manufacturing the black matrix on the TFT array substrate iscalled BOA (BM On Array, the Black Matrix is adhered on the arraysubstrate). BOA can solve the problems that the shielding areas do notmatch due to the upper, lower substrates misalignment, whichparticularly useful to the curved display. COA (Color filter On Array)technology is a skill to manufacture the RGB color resists which arepreviously manufactured on the color filter on the TFT array substrate.The COA technology can improve the signal delay on the metal line toraise the panel aperture ratio and improve the display quality of thepanel.

FIG. 1 is a diagram of a color filter after a black matrix ismanufactured. As shown in FIG. 1, the black matrix 200 is a firstmanufacture process of the color filter 100. Therefore, referring thealignment mark of the previous process is not necessary for themanufacture process of the black matrix. In the liquid crystal displaypanel of BOA structure, the black matrix is manufactured at onside ofthe array substrate. Before manufacturing the black matrix, theprocesses of other patterns have already been accomplished. Thus,referring the alignment mark of the previous process is not necessary asmanufacturing the black matrix. However, the black matrix has higher OD(optical density). Thus, it will cause interference to the recognitionto the mask alignment mark after the coating, and might result in theunable alignment of the stepper. If the black matrix material havinglower optical density is used, the recognition ability of the alignmentmark after coating can be improved but the shielding result of the blackmatrix can be seriously influenced.

FIG. 2 is a diagram of a TFT array substrate coated a black matrix colorresist system. FIG. 3 is a sectional diagram of a circle area in FIG. 2.As shown in FIG. 2, FIG. 3, after the TFT array substrate 300 is coatedwith the black matrix thin film 400, the black matrix thin film 400completely covers the alignment mask 500. Because the typical value ofthe thickness of the black matrix thin film 400 is 1 μm, and after itcovers the alignment mask 500, the level difference d1 of the positionof the alignment mask 500 and the adjacent area is reduced. Therefore,even utilizing the method of contour recognition is very difficult torecognize the accurate position of the alignment mask 500.

SUMMARY OF THE INVENTION

An objective of the present invention is to provide a manufacture methodof a black matrix. By increasing the level differences of the positionsof the alignment marks and adjacent areas, the method of contourrecognition can be utilized to recognize positions of the alignmentmarks after the black matrix thin film is coated. After accuratelypositioning, the black matrix thin film is patterned to form a designpattern of the black matrix for solving the issue that the alignmentmarks are difficult to be recognized in the manufacture process of theblack matrix thin film in the BOA structure.

For realizing the aforesaid objective, the present invention provides amanufacture method of a black matrix, comprising steps of:

-   -   step 1, providing a substrate, and a plurality of alignment        marks are provided on the substrate;    -   step 2, manufacturing an organic photoresist layer on the        substrate, and the photoresist layer comprises a plurality of        organic photoresist blocks respectively covering the plurality        of alignment marks;    -   step 3, coating a black matrix thin film on the substrate and        the organic photoresist layer;    -   step 4, employing a contour recognition apparatus to recognize        positions of the alignment marks based on level differences        formed by the positions of the alignment marks and adjacent        areas on the substrate, and after accurately positioning,        patterning the black matrix thin film to form the black matrix.

In the step 1, the substrate is a TFT array substrate.

The substrate is a rectangular structure, and there are four alignmentmarks respectively located at four corners of the rectangular.

Both the alignment marks and the organic photoresist blocks are crossstructures, and sizes of the two are the same.

The organic photoresist blocks are color resist blocks.

A thickness of the organic photoresist blocks is 3 μm.

A thickness of the black matrix thin film is 1 μm.

In the step 4, the level differences of the positions of the alignmentmarks and adjacent areas are larger than 2 μm.

In the step 4, the level differences of the positions of the alignmentmarks and adjacent areas are 3 μm.

In the step 4, the contour recognition apparatus is a camera lens havingdifference modes or a CCD probe.

The present invention further provides a manufacture method of a blackmatrix, comprising steps of:

-   -   step 1, providing a substrate, and a plurality of alignment        marks are provided on the substrate;    -   step 2, manufacturing an organic photoresist layer on the        substrate, and the photoresist layer comprises a plurality of        organic photoresist blocks respectively covering the plurality        of alignment marks;    -   step 3, coating a black matrix thin film on the substrate and        the organic photoresist layer;    -   step 4, employing a contour recognition apparatus to recognize        positions of the alignment marks based on level differences        formed by the positions of the alignment marks and adjacent        areas on the substrate, and after accurately positioning,        patterning the black matrix thin film to form the black matrix;    -   wherein in the step 1, the substrate is a TFT array substrate.    -   wherein the substrate is a rectangular structure, and there are        four alignment marks respectively located at four corners of the        rectangular;    -   wherein both the alignment marks and the organic photoresist        blocks are cross structures, and sizes of the two are the same;    -   wherein the organic photoresist blocks are color resist blocks;    -   wherein in the step 4, the contour recognition apparatus is a        camera lens having difference modes or a CCD probe.

The benefits of the present invention are: the present inventionprovides a manufacture method of a black matrix. The COA technology isutilized to manufacture the organic photoresist blocks with a largerthickness on the alignment marks. Then, the black matrix thin filmcovers on the organic photoresist blocks to tremendously increase thelevel differences of the positions of the alignment marks and adjacentareas. Thus, the contour recognition apparatus can be employed toaccurately recognize positions of the alignment marks. Accordingly, theissue that the alignment marks are difficult to be recognized after theblack matrix thin film is coated in the BOA process can be solved.

In order to better understand the characteristics and technical aspectof the invention, please refer to the following detailed description ofthe present invention is concerned with the diagrams, however, providereference to the accompanying drawings and description only and is notintended to be limiting of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

The technical solution and the beneficial effects of the presentinvention are best understood from the following detailed descriptionwith reference to the accompanying figures and embodiments.

In drawings,

FIG. 1 is a diagram of a color filter after a black matrix ismanufactured;

FIG. 2 is a diagram of a TFT array substrate coated a black matrix colorresist system;

FIG. 3 is a sectional diagram of a circle area in FIG. 2;

FIG. 4 is a diagram of the step 1 in a manufacture method of a blackmatrix according to the present invention;

FIG. 5 is a sectional diagram of A-A portion in FIG. 4;

FIG. 6 is a diagram of the step 2 in a manufacture method of a blackmatrix according to the present invention;

FIG. 7 is a sectional diagram of A-A portion in FIG. 6;

FIG. 8 is a diagram of the step 3 in a manufacture method of a blackmatrix according to the present invention;

FIG. 9 is a sectional diagram of A-A portion in FIG. 8;

FIG. 10 is a diagram of the step 4 in a manufacture method of a blackmatrix according to the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

For better explaining the technical solution and the effect of thepresent invention, the present invention will be further described indetail with the accompanying drawings and the specific embodiments.

Please refer to FIGS. 4-10. The present invention provides a manufacturemethod of a black matrix, comprising steps of:

-   -   step 1, as shown in FIGS. 4-5, providing a substrate 1, and a        plurality of alignment marks 14 are provided on the substrate 1.

Specifically, the substrate 1 is a TFT array substrate.

Preferably, the substrate 1 is a rectangular structure, and there arefour alignment marks 14 respectively located at four corners of therectangular.

Preferably, the alignment marks 14 are cross structures.

-   -   step 2, as shown in FIGS. 6-7, manufacturing an organic        photoresist layer on the substrate 1, and the photoresist layer        comprises a plurality of organic photoresist blocks 2        respectively covering the plurality of alignment marks 14.

Specifically, the organic photoresist layer comprises four organicphotoresist blocks 2. The shape of the organic photoresist block 2 isthe same as that of the alignment mark 14, which both are crossstructures. The size of the organic photoresist block 2 is basically thesame as the size of the alignment mark 14.

Specifically, the organic photoresist blocks 2 are color resist blocks,such as red, green, or blue resist blocks.

Preferably, a thickness d2 of the organic photoresist blocks 2 is 3 μm.The organic photoresist blocks 2 are employed to increase the leveldifferences of the positions of the alignment marks 14 and adjacentareas on the substrate 1 to promote the recognition accuracy of thecontour recognition apparatus.

The COA (color filter on array) technology is a skill to manufacture thecolor filter (generally formed with color resists) on the TFT arraysubstrate. The step 2 utilizes the method of the COA technology tomanufacture the organic photoresist blocks (such as color resist blocks)on the alignment mark of the TFT array substrate. Thus, the leveldifferences of the positions of the alignment marks 14 and adjacentareas on the substrate is increased and beneficial for employing thecontour recognition apparatus to recognize positions of the alignmentmarks 14 in the following step and promoting the recognition accuracy.

-   -   step 3, as shown in FIGS. 8-9, coating a black matrix thin film        3 on the substrate 1 and the organic photoresist layer.

Preferably, a thickness of the black matrix thin film 3 is 1 μm.

-   -   step 4, as shown in FIG. 10, employing a contour recognition        apparatus to recognize positions of the alignment marks 14 base        on level differences d3 formed by the positions of the alignment        marks 14 and adjacent areas on the substrate 1, and after        accurately positioning, patterning the black matrix thin film 3        to form the black matrix 4.

Specifically, the level differences d3 of the positions of the alignmentmarks 14 and adjacent areas on the substrate 1 are 3 μm.

In the TFT array substrate according to prior art, the level differencesd1 of the positions of the alignment marks and adjacent areas aregenerally smaller than 1 μm. Because the level difference is smaller,the method of contour recognition is difficult to recognize the accuratepositions of the alignment marks. In the manufacture method of a blackmatrix according to the present application, by adding an organicphotoresist block 2 on the alignment mark 14, the level difference d3 ofthe position of the alignment mark 14 and adjacent area on the substrate1 is larger than 2 μm after the black matrix thin film 3 is coated.Thus, the accurate recognition of the contour recognition apparatus tothe position of the alignment mark 14 can be ensured; in comparison withthe method of directly coating the black matrix thin film on thealignment mark according to prior art, the level differences of thepositions of the alignment marks and adjacent areas are tremendouslyincreased to promote the recognition accuracy of the contour recognitionapparatus.

Specifically, the contour recognition apparatus is a camera lens havingdifference modes or a CCD (Charge-coupled Device) probe.

In conclusion, the present invention provides a manufacture method of ablack matrix. The COA technology is utilized to manufacture the organicphotoresist blocks with a larger thickness on the alignment marks. Then,the black matrix thin film covers on the organic photoresist blocks totremendously increase the level differences of the positions of thealignment marks and adjacent areas. Thus, the contour recognitionapparatus can be employed to accurately recognize positions of thealignment marks. Accordingly, the issue that the alignment marks aredifficult to be recognized after the black matrix thin film is coated inthe BOA process can be solved.

Above are only specific embodiments of the present invention, the scopeof the present invention is not limited to this, and to any persons whoare skilled in the art, change or replacement which is easily derivedshould be covered by the protected scope of the invention. Thus, theprotected scope of the invention should go by the subject claims.

What is claimed is:
 1. A manufacture method of a black matrix,comprising steps of: step 1, providing a substrate, and a plurality ofalignment marks are provided on the substrate; step 2, manufacturing anorganic photoresist layer on the substrate, and the photoresist layercomprises a plurality of organic photoresist blocks respectivelycovering the plurality of alignment marks; step 3, coating a blackmatrix thin film on the substrate and the organic photoresist layer;step 4, employing a contour recognition apparatus to recognize positionsof the alignment marks based on level differences formed by thepositions of the alignment marks and adjacent areas on the substrate,and after accurately positioning, patterning the black matrix thin filmto form the black matrix.
 2. The manufacture method of the black matrixaccording to claim 1, wherein in the step 1, the substrate is a TFTarray substrate.
 3. The manufacture method of the black matrix accordingto claim 1, wherein the substrate is a rectangular structure, and thereare four alignment marks respectively located at four corners of therectangular.
 4. The manufacture method of the black matrix according toclaim 1, wherein both the alignment marks and the organic photoresistblocks are cross structures, and sizes of the two are the same.
 5. Themanufacture method of the black matrix according to claim 1, wherein theorganic photoresist blocks are color resist blocks.
 6. The manufacturemethod of the black matrix according to claim 1, wherein a thickness ofthe organic photoresist blocks is 3 μm.
 7. The manufacture method of theblack matrix according to claim 6, wherein a thickness of the blackmatrix thin film is 1 μm.
 8. The manufacture method of the black matrixaccording to claim 7, wherein in the step 4, the level differences ofthe positions of the alignment marks and adjacent areas are larger than2 μm.
 9. The manufacture method of the black matrix according to claim8, wherein in the step 4, the level differences of the positions of thealignment marks and adjacent areas are 3 μm.
 10. The manufacture methodof the black matrix according to claim 1, wherein in the step 4, thecontour recognition apparatus is a camera lens having difference modesor a CCD probe.
 11. A manufacture method of a black matrix, comprisingsteps of: step 1, providing a substrate, and a plurality of alignmentmarks are provided on the substrate; step 2, manufacturing an organicphotoresist layer on the substrate, and the photoresist layer comprisesa plurality of organic photoresist blocks respectively covering theplurality of alignment marks; step 3, coating a black matrix thin filmon the substrate and the organic photoresist layer; step 4, employing acontour recognition apparatus to recognize positions of the alignmentmarks based on level differences formed by the positions of thealignment marks and adjacent areas on the substrate, and afteraccurately positioning, patterning the black matrix thin film to formthe black matrix; wherein in the step 1, the substrate is a TFT arraysubstrate. wherein the substrate is a rectangular structure, and thereare four alignment marks respectively located at four corners of therectangular; wherein both the alignment marks and the organicphotoresist blocks are cross structures, and sizes of the two are thesame; wherein the organic photoresist blocks are color resist blocks;wherein in the step 4, the contour recognition apparatus is a cameralens having difference modes or a CCD probe.
 12. The manufacture methodof the black matrix according to claim 11, wherein a thickness of theorganic photoresist blocks is 3 μm.
 13. The manufacture method of theblack matrix according to claim 12, wherein a thickness of the blackmatrix thin film is 1 μm.
 14. The manufacture method of the black matrixaccording to claim 13, wherein in the step 4, the level differences ofthe positions of the alignment marks and adjacent areas are larger than2 μm.
 15. The manufacture method of the black matrix according to claim14, wherein in the step 4, the level differences of the positions of thealignment marks and adjacent areas are 3 μm.